Plants grow in complete darkness in an acetate medium that replaces biological photosynthesis. Credit: Marcus Harland-Dunaway / UCR
Researchers are developing artificial photosynthesis to help make food production more energy efficient on Earth, and perhaps one day on Mars.
For millions of years, photosynthesis has evolved in plants to convert water, carbon dioxide, and sunlight energy into plant biomass and the foods we eat. However, this process is very inefficient, with only about 1% of the energy found in sunlight ending up in the plant. Researchers at the University of California, Riverside and the University of Delaware have found a way to avoid the need for biological photosynthesis and create foods independent of sunlight through artificial photosynthesis.
The new research, published on June 23, 2022 in the journal Nature Food, uses a two-step electrocatalytic process to convert carbon dioxide, electricity and water into acetate, the form of the main component of vinegar. Food-producing organisms consume acetate in the dark to grow. Combined with solar panels to generate electricity to power electrocatalysis, this hybrid organic-inorganic system could increase the conversion efficiency of sunlight into food, up to 18 times more efficient for some foods.
“With our approach we tried to identify a new way of producing food that could break the limits normally imposed by biological photosynthesis,” said corresponding author Robert Jinkerson, assistant professor of chemical and environmental engineering at UC Riverside.
In order to integrate all the components of the system, the output of the electrolyzer was optimized to support the growth of food-producing organisms. Electrolyzers are devices that use electricity to convert raw materials such as carbon dioxide into molecules and useful products. The amount of acetate produced increased while the amount of salt used decreased, resulting in the highest levels of acetate ever produced in an electrolyzer to date.
“Using a state-of-the-art tandem CO2 electrolysis configuration developed in our laboratory, we were able to achieve high selectivity to acetate which cannot be accessed by conventional CO2 electrolysis pathways,” he said. say the corresponding author Feng Jiao University. of Delaware.
Experiments showed that a wide range of food-producing organisms can be grown in the dark directly at the outlet of the acetate-rich electrolyzer, including green algae, yeast, and mushroom-producing fungal mycelium. Producing algae with this technology is about four times more energy efficient than growing them photosynthetically. Yeast production is approximately 18 times more energy efficient than as normally grown with sugar extracted from corn.
“We were able to grow food-producing organisms without any contribution from biological photosynthesis. Typically, these organisms are grown with plant-derived sugars or petroleum-derived inputs, which is a product of biological photosynthesis that took place long ago. This technology is a more efficient method of converting solar energy into food, compared to food production that is based on biological photosynthesis, “said Elizabeth Hann, a PhD candidate at Jinkerson Lab and lead co-author of the study.
The potential of using this technology to grow crop plants was also investigated. Kaupin, tomato, tobacco, rice, canola, and green peas could use acetate carbon when grown in the dark.
“We found that a wide range of crops could take the acetate we provided and incorporate it into the major molecular blocks that an organism needs to grow and thrive. With a little improvement and engineering that we are currently working on, we could grow crops. with acetate as an additional energy source to increase crop yields, ”said Marcus Harland-Dunaway, a PhD candidate at the Jinkerson Laboratory and lead co-author of the study.
By freeing agriculture from total dependence on the sun, artificial photosynthesis opens the door to innumerable possibilities for food cultivation in the increasingly difficult conditions imposed by anthropogenic climate change. Drought, floods, and reduced land availability would be a lesser threat to global food security if crops for humans and animals were grown in controlled, resource-consuming environments. Crops could also be grown in cities and other areas currently unsuitable for agriculture, and even provide food for future space explorers.
“Using artificial photosynthesis approaches to produce food could be a paradigm shift for how we feed people. By increasing the efficiency of food production, less land is needed, reducing the impact that agriculture has on the and for agriculture in non-traditional environments, such as outer space, increased energy efficiency could help feed more crew members with fewer inputs, “Jinkerson said.
This approach to food production was presented at NASA’s Deep Space Food Challenge, where it was a Phase I winner. The Deep Space Food Challenge is an international competition where prizes are awarded to teams for creating food technologies. new and game-changing ones that require minimal inputs and maximize the production of safe, nutritious, and enjoyable food for long-term space missions.
“Imagine someday giant ships growing tomato plants in the dark and on Mars; how much easier would that be for future Martians?” said co-author Martha Orozco-Cárdenas, director of the UC Riverside Plant Transformation Research Center.
Reference: “A hybrid inorganic-biological artificial photosynthesis system for energy-efficient food production” by Elizabeth C. Hann, Sean Overa, Marcus Harland-Dunaway, Andrés F. Narvaez, Dang N. Le, Martha L. Orozco-Cárdenas, Feng Jiao and Robert E. Jinkerson, June 23, 2022, Nature Food.DOI: 10.1038 / s43016-022-00530-x
Andres Narvaez, Dang Le and Sean Overa also contributed to the research. The open access document is entitled “A hybrid system of inorganic-biological artificial photosynthesis for energy efficient food production”.
The research was supported by the Translational Research Institute for Space Health (TRISH) through NASA (NNX16AO69A), the Foundation for Research in Agriculture and Food (FFAR), the Foundation Link, the U.S. National Science Foundation and the U.S. Department of Energy. The content of this publication is the sole responsibility of the authors and does not necessarily represent the official views of the Foundation for Agri-Food Research.